1. Technical Field
Embodiments of the present invention generally relates to an electrophotographic image forming apparatus such as a copier, a facsimile machine, a printer, or a multifunction peripheral (MFP, i.e., a multifunction machine) having at least two of copying, printing, facsimile transmission, plotting, and scanning capabilities.
2. Description of the Related Art
Image forming apparatuses such as copiers and printers generally include a transfer roller to press against an image bearer, and a contact therebetween is called “transfer nip” (i.e., a transfer position). It is possible that toner transferred from the image bearer adheres to the transfer roller. Then, when a recording medium such as a paper sheet is nipped in the transfer nip, it is possible that a back side or an edge face of the recording medium is soiled with toner transferred from the transfer roller. To prevent such soil of toner of the sheet, for example, a cleaning bias different from a transfer bias is applied to the transfer roller in intervals between sheets transported to the transfer nip between the transfer roller and the image bearer.